Rugby stars Sonny Bill Williams and Quade Cooper were both winners in the boxing ring in Brisbane on Friday.

Last Updated: 08/02/13 4:53pm

Sonny Bill Williams (L): Victory over Frans Botha was not without controversy

Dual-code New Zealand international Williams extended the unbeaten start to his boxing career as he claimed a 10-round points win over former world title challenger Frans Botha to claim the WBA International heavyweight belt.

South African Botha, a 44-year-old who has fought the likes of Lennox Lewis, Mike Tyson and Wladimir Klitschko, is by far the biggest scalp on Williams' 6-0 record.

But even though the judges returned scores of 97-91 (twice) and 98-94, the contest was not without controversy as Botha's corner and many others in the arena were apparently under the impression that it would be a 12-rounder.

Williams was shaken badly in what proved to be the final round but survived to the bell and emerged with the victory.

Australia fly-half Quade Cooper, who was making his boxing debut, had a much more straightforward evening as knocked out Barry Dunnett in the first round.

Cooper send his opponent crashing to the canvas with a right hook to ensure that the cruiserweight bout, scheduled for four rounds, would not go the distance.